What is the legal term for substituting an existing contract with a new one?

The legal term for substituting an existing contract with a new one is novation. In the context of contract law, novation is the act of replacing an old contract with a new contract, in which the original party's obligations are transferred to a new party, and the original party is released from any further obligations under the old contract.

This process requires the consent of all parties involved: the party being replaced, the new party taking on the obligations, and the other party to the original contract. The new contract essentially takes the place of the old one, allowing for modifications of the terms, parties, or both while maintaining the underlying agreement's validity.

Revocation refers to the act of withdrawing an offer or taking back an acceptance before a contract is formed, which does not involve the substitution of contracts. Rescission involves the annulment of a contract, returning the parties to their pre-contractual position without necessarily replacing it with a new one. Mutual consent refers to the agreement of all parties to a contract but does not specifically denote the substitution of an old contract with a new one. Thus, novation is the precise term for this legal process.